Page end indicator



March 5, 1935. M. M. MUNK 1,993,038

PAGE END INDI CATOR Filed Jan. 10, 1934 2 Sheets-Sheet 1 I III I II II lillll March 5, 1935. v I M. M. MUNK 1,993,038

PAGE END INDICATOR Filed Jan. 10, 1934 2 Sheets-Sheet 2 Patented Mar. 5, 1935 UNITED STATES PATENT OFFICE '1- Claims.

This invention relates to page end indicators for typewriters. Its broad general purpose is to provide for such indicator or signaling device which is mechanically driven, exact, positive,

reliable, and automatic, and which never blocks the letter in its motion.

7 Page end indicators of that kind proposed before contain as a cardinal element some kind of a paper feeler, and this feeler is liable to block the letter on its return motion. The gist of the present invention is the absence of a paper feeler, and the substitution therefor of a driver, such as a. friction roller in engagement with the letter but not with the platen. This driver diflers from a paper feeler in that it is not actively affected by the presence or absence of the letter, but by the motion of the letter. Such driver is superior to a feeler in that it leads to a simpler mechanism and does not block the letter. It is accordingly an object of the present invention to provide for a. page end indicator without a paper feeler.

Another object of the invention is to provide for such indicator driven in combination by the advancing letter.

Still another object of the invention is to provide for a page end indicator comprising as driver therefor a roller adapted to be driven by the letter but not by the platen.

A still other object of the invention is to provide for such indicator the motion of which is governed by an algebraic combination of the platent motion and the letter motion.

These and other desirable objects and ad- 35 vantages of the present invention will be illustrated in the accompanying drawings and described in the specification,- a certain preferred embodiment being disclosed by way of illustration only, for, since the underlying principles may be incorporated in other specific devices, it is not intended to be limited to the one here shown, except as such limitations are clearly imposed by the appended claims.

In the drawings like numerals refer to similar parts throughout the several views, of which Fig. 1 is a large scale sectional view of the page end indicator,

Fig. 2 represents the front elevation of a type writer having the page end indicator of Fig. 1 mounted therein.

Fig. 3 is a partial cross section on the line 3--3,

Fig. 4 is a partial side elevation on the line 4-4,

Fig. 5 is a partial cross section on the line 5-5, and

Fig. 6 is a partial cross section on the line 65.

Turning now to Fig. 1, there is illustrated a cylindrical typewriter'platen 11, its left arbor 14 being shown to be supported by the, left platen bearing 13 of the carriage; the right platen arbor and platen bearing cooperating exactly alike. Each of the arbors supports revolubly a sleeve, 17 at the left and 17' at the right; and these two sleeves are mediately and rigidly connected 'by the bar 42, extending from one side of the carriage to theother side, so that the indicator frame formed by this bar and the sleeves, and all mechanisms supported by it, can swing freely around the platen axis. It doesso swing unto the rear under the action of its own gravity until it leans against the letter guide 15 on a projecting point 41 to be described farther below.

The frame thus describedcarries a shaft 20 reaching from the left side of the carriage up to about its center. It is revolubly mounted in the three bearings 4'7, 38, and 40, provided in part 21, to be described farther below, and in the brackets 37 and 39 fastened to bar 42.

Shaft 20 is driven by a friction roller 41 fixed to its right end. This roller leans against the letter guide 15, either immediately, in which case. it is braked thereby and kept from rotating, or with the letter 47 interposed between it and the letter guide. In that case the driver 41 is frictiona1 engagement with the letter, and is turned if the letter is advanced or moved back. Attention is directed to the fact that the driver 41 is never in contact or engagement with the platen 11.

Shaft 20 further supports freely revoluble thereon the spur gear sleeve 34 with two spur gears, 35 and 36formed thereon. Spur gear 36 is in mesh with a third spur gear 12 fixed to and provided, on the cylindrical platen 11. When the platen is turned, spur gear 36 also turns, and it constitutes a second driver for the page end indicator. Gear 35 cooperates as a sun gear in an epicyclic planetary gear train composed further of the annular gear 32 and the planet gears 33. The annular gear is fixed to shaft 20 and is thus seen to be driven by the driving roller 41 and hence by the letter. The sun gear 'is driven by the platen. The planetary'gears 33 are carried by the wheel 29, revolubly mounted on shaft 20 and acting as the actuator of the page end indicator, as will be shown.

It is thus seen that the two drivers 41 and 36, representing respectively the motion of the letter and of the platen, combine in driving the actuator 29, so that the motion of the actuator represents the composite effect of the two independent motions of the drivers. If the driver" 41 rotates.

at all, the letter occupying the space' between it and the letter guide and being in the process of being advanced, it rotates in a direction opposite to the direction of rotation of the driving spur gear 36. The rate of turn of the two drivers is not much different, but the gear ratio between the two drivers on one hand and the actuator on the other hand is distinctly unequal, that between the driving spur gear and the actuator being much larger than that between the driving roller and the actuator. In consequence the influence of the driving roller on the actuator motion exceeds the influence of the driving spur gear, bringing about that the actuator turns in one direction if driven by both drivers, and turns in the opposite direction if driven by the driving spur gear only (the driving roller being then out of engagement with the letter and kept stationary by the friction between it and the letter guide).

The actuator 29 constitutes further one of the simply rotating members in a frictional epicyclic differential gear, comprising further the planetary conical friction roller 28, and two conical concentric rims, one on the ratchet wheel .22 and the other on the brake wheel 21. Planet roller 28 revolves freely about the pin 27 fastened to the indicator hub 25. Brake wheel 21 is stationary and rigidly connected to sleeve 17 being integral therewith and forming the connecting member between this sleeve 17 and bar 42. Ratchet wheel 22 is freely rotatable about shaft 20, except for the action of its ratchet pawls 23 swinging on pins 24 of the brake wheel 21. These pawls engage ratchet teeth provided on the hub of the ratchet wheel. They prohibit the rotation of the ratchet wheel in one direction, but permit its free rotation in the other direction, viz. the front rim moving up. The conical rim of brake wheel 21 does not extend all way around, but it is inter rupted by a gap 44. i The indicator hub 25 carries the graduated indicator rim 26 elastically clamped thereto. The latter is in frictional engagement with a small braking spring 46 fastened to bar 42. This frictional differential gear constitutes a means for transmitting the motion of the actuator 29 to the indicator 26. The transmittal takes place in whatever direction the actuator may turn, unless the planet roller 28 registers with the gap 44. In that case the motion is only transmitted one-way, namely when the ratchet wheel remains stationary under the action of the pawls, but when it rotates, the indicator remains stationary under the braking action of brake 46.

It is thus seen that the different elements rotate in a way compiled in the following table, the letter being advanced by rotating the platen:

Platen l1 Front up Driving spur gear 36 Front down Driving roller 41 Front up Actuator 29Driving roller engaged--- Front up Actuator 29Driving roller braked Front down Indicator 25 (Brake wheel 21 engaged)-Driving roller engaged Front down (1) Indicator 25 (Brake wheel 21 engaged)Driving roller braked Front up (4) Indicator 25 (Planet roller 28 registering with gap 44)-Driving roller engaged Stationary (2) Indicator 25 (Planet roller 28 registering with gap 44)Driving roller braked Front up (3) It is further seen that these different phases of motion occur in the order as indicated by the numerals in brackets at the end of the last lines. It becomes thus apparent that the indicator executes motions which make it suitable to indicate position where the page end registers with driv- I The indicator remains there stationary until the letter has reached that standard ing roller 41. The indicator assumes then a motion parallel to that of the platen, and during the second half of the letter indicates the number of lines left for printing, by numerals adjacent pointer 45.

A return motion of the letter reverses all motions, without interfering with the correctness of the indicator readings.

I claim:

1. A page end indicator for typewriters comprising signal means; drivers therefor including a friction roller adapted to be in driving engagement with the letter, and in braking engagement with the letter guide, means for combining the motions of the drivers, means for a two-way transmittal of the combined motion to the signal means, and means for changing said two-way transmittal to an one-way transmittal at a definite position of the signal means.

2. A page end indicator for typewriters comprising signal means; drivers therefor including a friction roller adapted for driving engagement only with the letter, means for combining the motions of the drivers, means for a two-way transmittal of the combined motion to the signal means, and means for changing said two-way transmittal to an one-way transmittal at a definite position of the signal means.

3. A page end indicator for typewriters comprising signal means, drivers therefor including a friction roller pressing the ,letter against the letter guide, means for combining the motions of the drivers, means for a two-way transmittal of the combined motion to the signal means, and means for changing said two-way transmittal to an one-way transmittal at a definite position of the signal means.

4. A page end indicator for typewriters, comprising signal means, drivers therefor including a driver adapted to be driven by the letter and braked when not so driven, means for combining the motions of the drivers, means for a two-way transmittal of the combined motion to the signal means, and means for changing said two-way transmittal to an one-way transmittal at a. definite position of the signal means.

5. A page end indicator for typewriters, comprising a. signal wheel, a stationary gapped brake wheel, a ratchet wheel, a platen actuated driver, another driver adapted to be actuated by the letter and tobe braked when not so driven, an actuator, a first epicyclic train connecting the drivers with the actuator, and a second epicyclic train connecting the actuator and both the ratchet wheel and brake wheel with the signal wheel.

6. A page end indicator for typewriters, comprising signal means, drivers therefor including a driver adapted to be driven by the letter in frictional engagement therewith and braked whenever out of such engagement, means for .combining the motion of the drivers, means for to the signal means, and means for changing said two-way transmittal to an one-way transmittal at a definite position of the signal means.

7. A- page end indicator for typewriters comprising'signal means, a first driver in motion while the letter is being advanced and stationary while the letter is not being advanced, a second driver in motion while the letter is being advanced through a portion of its course and stationary while the letter is being advanced through the remaining portion of its course and while the letter is not being advanced, means for combining the motions of the drivers, means for a twoway transmittal of the combined motion to the signal means, and means for changing said twoway transmittal to an one-way transmittal at a definite position of the signal means. 

